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Thread: PSU voltage rail discussion

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    Default PSU voltage rail discussion

    I am bringing this over from anandtech, because it is obvious not much discussion on this topic is going to go on over there

    Quote Originally Posted by beray
    That's because practically all "anyone" failed to recognize that 99.99999% of PSUs on the market are "12V single-rail" PSUs.

    Since they don't actually know about "12V single-rail" PSUs except aping the words, they failed to test for the inherent weakness of single-rail PSU design architecture assuming they even knew what that was.

    "12V single-rail" PSU designs are easily recognizable by reading a literate PSU label like THIS ONE

    The linked literate label indicated:

    3.3V and 5V on one rail.
    all 12V on one rail.
    -12 and 5Vsb on one rail.

    There is a standard test for single-rail architecture weakness and it is called a cross-regulation test.

    For example: 3.3V and 5V on one rail meant 3.3V can cause cross-regulation failure in 5V and vice-versa.

    In multi-rail, each one of the rails are independent from the others thus no cross-regulation problem.
    He is of course claiming that any PSU with a single transformer for the 12v rail and a single transformer for the 3.33v and 5v rails will fail in crossload testing. However, I have seen multiple crossload tests here on jonnyguru.com that disprove that.

    He even admits that 99% of PSUs are designed this way, but basically says that the Corsair HX620 and HX520 are faulty because of this and that a person should not buy them. So I suppose he expects them to go look for those 1% of PSUs out there that are true multi-rail 12V and maybe the .05% that have true rails for the 3.3v and 5v

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    Was there some sort of prior context?

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    A poster asked if his HX520 would be sufficient for a GTX280 and a heavy overclock.

    beray linked to a thread in which an author with an HX620 was having problems with constant reboots after installing an HD4870, although he tried another PSU and that did not fix the problem. Everyone else in the thread thought it might point to a motherboard problem.

    Beray took this thread and began bashing Corsair PSUs as insufficient and told the poster he should get another PSU, without directing him to the specific problem with the Corsairs.

    I stated that with his heavy overclock the HX520 might not be sufficient, but it probably still was fine...and that all the sites that I have read who have load tested the Corsair PSUs show they are excellent.

    He states that the people testing them apparently don't know about the inherent flaws in single rail systems where the 12V rail is a single rail and the 3.33 and 5 V share the same transformer (regardless of whether they have their own rectifiers or not)

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    Quote Originally Posted by HOOfan_1 View Post
    A poster asked if his HX520 would be sufficient for a GTX280 and a heavy overclock.

    beray linked to a thread in which an author with an HX620 was having problems with constant reboots after installing an HD4870, although he tried another PSU and that did not fix the problem. Everyone else in the thread thought it might point to a motherboard problem.

    Beray took this thread and began bashing Corsair PSUs as insufficient and told the poster he should get another PSU, without directing him to the specific problem with the Corsairs.

    I stated that with his heavy overclock the HX520 might not be sufficient, but it probably still was fine...and that all the sites that I have read who have load tested the Corsair PSUs show they are excellent.

    He states that the people testing them apparently don't know about the inherent flaws in single rail systems where the 12V rail is a single rail and the 3.33 and 5 V share the same transformer (regardless of whether they have their own rectifiers or not)
    Interesting. Well they do crossload fine. I don't specifically corssload units but at 100% with those kinds of units it typically has a heavy crossload given the high 12v capacity and they work fine. I think he may not quite understand the issue himself and the rest of his post is a headache.

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    well here is some insight into his background. I am barely even a layman when it comes to PSUs so I really haven't the knowledge to debate the subject.

    @HOOfan 1
    Find a real native English speaking PSU expert for your discussion...

    1 - I'm not a PSU expert, my PSU skill is JOE AVERAGE, my specialty is realtime graphic hardware. I do PSU when needed in my hardware requirement though graphic hardware do have a bad habit of extreme power requirement, I don't do PSU for a living.

    2 - I achieved my Engrish skill with a $30 3000-word dictionary, you can't really do much with 1-cent-per-word Engrish skill. But I'm doing OK with what little I'd invested, I did have more use for my 1-cent-per-word Engrish than some English natives with Master degree in English.

    3 - There're know nothing idiot experts wanting everything "factually corrected" to below gradeschool ignorance and stupidity.

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    @HOOfan 1
    Find a real native English speaking PSU expert for your discussion...

    1 - I'm not a PSU expert, my PSU skill is JOE AVERAGE, my specialty is realtime graphic hardware. I do PSU when needed in my hardware requirement though graphic hardware do have a bad habit of extreme power requirement, I don't do PSU for a living.

    2 - I achieved my Engrish skill with a $30 3000-word dictionary, you can't really do much with 1-cent-per-word Engrish skill. But I'm doing OK with what little I'd invested, I did have more use for my 1-cent-per-word Engrish than some English natives with Master degree in English.

    3 - There're know nothing idiot experts wanting everything "factually corrected" to below gradeschool ignorance and stupidity.
    1 - i THOUGHT i was JOE AVERAGE when it came to PSUs also, until i started reading here

    2 - Engrish? maybe he should learn how to write the word first and then bash us later!

    3 - i get my facts from a reliable source - like here!

    man what an ass
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    I think he was spelling it as Engrish to indicate that he is not a fluent speaker.

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    still he comes across as stupid and an ass
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    here is some more of what he has had to say

    Quote Originally Posted by beray
    Yes, there are experts be stupid enough to test cross-regulation between 3.3V and 5V rail against 12V rail. Even though they are independent separate rails, not susceptible to cross-regulation failure from each other.

    The real experts would do 3.3V against 5V and vice-versa as they are both on one single rail and would have cross-regulation problem with each other.

    The real experts would do 12V against other 12V as they are all on one single rail and would have cross-regulation problem with each other.

    single-rails are susceptible to cross-regulation, multi-rails don't as they are "independent rails/supplies".
    Is there any reason to crossload the 3.33V rail against the 5V rail???

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    Quote Originally Posted by HOOfan_1 View Post
    here is some more of what he has had to say



    Is there any reason to crossload the 3.33V rail against the 5V rail???
    No especially since the 3.3v hardly ever gets loaded which measn it is almost always 5v high crossloaded and they work just fine. BTW indy regulation means the 3.3v and 5v are independatly regulated rails. Also units like the CWT PCU and others generate their 3.3v or 5v from a strait 12v DC-DC conversion and in the case of the PUC from seperate 12v sources.

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